A mysterious emergency at the nursing home. A terrible virus that may spark a pandemic. And a puzzle left over from wartime Yugoslavia, not yet solved. In the rickety treehouse, plans are hatched, insights are mulled over, and adventures are instigated--with thrilling results. Join up with Avi, Shimon, and Mendy, three lively friends whose endearing personalities and boundless energy make them lots of fun to be around, if you're not afraid of the occasional lurking danger! This book has all the elements of a great novel for kids. Fun, fast-paced, with lots of lessons in faith and trust along the way, it's a story that spans modern-day New York to wartime Yugoslavia in an intricately-woven plot that will keep readers guessing till the very end.